Air-blast grain huller

ABSTRACT

The air-blast grain huller consists of a mixing tube with a contractor at the entry of the unscoured grain into its channel, and a nozzle placed in the contractor to supply air into the tube. Mounted in the nozzle hole is a stem, one end thereof being disposed within the contractor. The channel of the mixing tube expands stepwise in the axial direction away from the nozzle, while in the places of passage from one step of the tube to another there are made ports for additional air injection into the channel.

United States Patent 1 1 Zhislin et al.

[ Nov. 5, 1974 1 AIR-BLAST GRAIN HULLER [76] lnventors: Yakov MoiseevichZhislin, 13

proezd Mariinoi .Roschi, 44/46, kv. 35; Alexandr Eliseevich Krikunov,prospekt Mira, 7, kv. 20; Alexandr Yakovlevich Sokolov, ulitsaPanfilova. 18a, kv. 30; Alexei llvanovich Ivanoz, Veernaya ulitsa, 3,korpus 6, kv. 77; Albert Yakovlevich Leikin, Trifonovskaya ulitsa, 54,kv. 193; Efim Naumovich Grinberg, proezd Nansena, 6, korpus 2, kv. 77;Vyacheslav Dmitrievich Vinogradov, ulitsa admirala Makarova, 21, kv. 58;Z inaida Solomonoyna Yanovskaya, ulitsa Garibaldi, 27, korpus 1, kv. 167; Valery Andreevich Bykov, Krasnogvardeisky bulvar, 7, kv. 11,

all of Moscow, USSR.

[22] Filed: Feb. 24, 1972 [21] Appl. No.: 229,028

[52] US. Cl 99/519, 99/614, 99/623 [51] Int. Cl 45c 39/00 [58] Field ofSearch 99/2338, 525, 600, 614, 99/623,519; l5/3.l3

[56] References Cited UNITED STATES PATENTS 18,177 9/1857 Ager .1 99/614X 134,619 1/1873 Vandegrift 99/600 X 175,148 3/1876 Peabody 258,3415/1882 Ager 775,098 11/1904 Welch.... 777,986 12/1904 Welch 2,759,5118/1956 Jacobson 3,158,187 11/1964 Smith 15/313 X FOREIGN PATENTS ORAPPLICATIONS 545,301 8/1957 Canada .l 99/525 505,898 9/1954 Canada99/2338 622,103 4/1949 Great Britain 99/2338 1,188,089 4/1970 GreatBritain 99/2338 Primary Examiner-Harvey C. Horhsby Attorney, Agent, or Firm-Waters, lRoditi, Schwartz & Nissen 1 1 ABSTRACT The air-blast grainhuller consists of a mixing tube with a contractor at the entry of theunscoured grain into its channel, and a nozzle placed in the contractorto supply air into the tube. Mountedin the nozzle hole is a stem, oneend thereof being disposed within the contractor.

The channel of the mixing tube expands stepwise in the axial directionaway from the nozzle, while in the places of passage from one step ofthe tube to another there are made ports for additional air injectioninto the channel. 7 1

1 Claim, 1 Drawing Figure AIR-BLAST GRAIN HULLER The present inventionrelates to air-blast grain hullers employed in the groats, mixed feed,confectionery, and butter-and-fats industries, and can be mosteffectively utilized for hulling groats and filmy crops.

Known in the art are air-blast grain hulling devices, comprising amixing tube disposed in a substantially vertical position and having acontractor at the entry of the unscoured grain into its channel, and anozzle mounted in the tube contractor, through which nozzle air is fed.

In the known devices the nozzle is made with an open round outlet holewhose diameter is near to the grain size, which limits grainconcentration in the air jet and, respectively, the productive capacityof the device, since the ratio of the jet perimeter, within which grainis injected, to the sectional area of the jet is relatively small.

Besides that, in the free space of the contractor between the nozzle andthe entry of the mixing tube channel the grain is strongly stirred bythe airjet, which results in the grain kernels being damaged. The innerchannel in the middle part of the mixing tube in the known devices has aconstant cross section along its length, thus limiting the possibilitiesof its elongation because of aerodynamic resistance and preventingcomplete utilization of the air jet energy for grain hulling. The designof the nozzle has no provisions for regulating the size of the nozzleoutlet hole and the air jet cross section, which is necessary tooptimize the conditions of the air-blast hulling process.

In the known devices the mixing tube is made in the form of a solidhollow element, thus requiring its complete replacement in case of apartial wear of the walls at the channel entry. What is more, thematerial of which the mixing tubes are made does not always securesufficiently intense grain friction against the tube walls, whichadversely affects the hulling efficiency, particularly for grains havinga shell grown tight with the kernel, for example, barley grains. Asignificant current velocity at the exit from the mixing tube causesintense splitting of the kernels.

It is an object of the present invention to provide an air-blast huller,wherein the nozzle and the mixing tube would be made so as to raise theoutput of the huller through enhancing grain concentration in the airflow.

Another object of the present invention is to provide an air-blasthuller, wherein grain splitting would be reduced.

A further object of the present invention is to provide an air-blasthuller with maximum utilization of the air flow energy for the hullingprocess.

A still further object of the present invention is to provide anair-blast huller, wherein the hulling process would be swift.

With these and other objects in view, in an air-blast grain huller,comprising a mixing tube disposed in a substantially vertical positionand having a contractor at the entry of the unscoured grain into itschannel, and a nozzle mounted in the tube contractor, through whichnozzle air is fed, according to the invention, placed in the hole of thenozzle coaxially therewith is a stem, one end of which is located withinthe contractor of the mixing tube, the channel of thelatter expandingstepwise in the axial direction away from the nozzle,

and ports being provided in the tube, in the passages between its steps,for additional air injection thereinto.

Due to the location of the stem in the nozzle the air 5 jet acquires atubular shape, thus raising grain concentration in the jet, since ascompared to a continuous jet section, a significant gain is achieved inthe ratio of the outer perimeter of the injection jet to itscross-sectional area, and hence, in the ratio of the amount of injectedgrain to air consumption.

Location of one of the stem ends within the contractor of the mixingtube precludes strong stirring and splitting of grain therein, as thegrains contacting the jet are retained by the stem and are entrainedtherealong into the channel of the mixing tube.

The stepwise expansion of the channel of the mixing tube reduces itsaerodynamic resistance, which permits increasing its length and,accordingly, raising the utilization factor of the air jet energy, whilethe shock waves produced by the abrupt expansion of the air flow in thepassages from one tube step to another intensify the hulling process.

The additional air injection through the holes in the passages from onestep to another strengthens the shock waves, and also causes partialbraking of the air flow by the new air masses involved thereinto.

Advantageously, the stem portion disposed in the nozzle and thecontractor should be made narrowing in the axial direction from thenozzle toward the mixing tube channel, the stem itself being placed inthe nozzle so as to be capable of adjustment displacements.

This makes possible regulating the dimensions of the nozzle outlet holeand the dimensions of the air jet cross section in accordance with thegrain size and moisture and the strength of its shell, thus enabling thechoice of optimum values of said dimensions to attain a maximum hullingeffect.

Preferably, each step of the channel should be formed by a separate tubemounted so, that the outlet hole of the preceding tube is disposed inthe contractor of the subsequent one, the tube itself being made as aseries of hollow sleeves enclosed in a casing, and the holes foradditional air injection into the channel being formed by thesecontractors and the lower edges of the tubes.

Assembling the mixing tube from separate tubes provides for fastdismantling of the device, and making each tube as a set of sleevespermits replacing the sleeves or changing their places with their wear,thus extending the life of the huller.

it is also advisable producing the sleeves from an abrasive material,and making the sleeves of each tube, starting from the second one, withholes of two different diameters in order to place them so as to form astepped channel.

Such a design of the sleeves helps to intensify the hulling process,since it increases the grains friction against the inner walls of thechannel and enhances the destructive effect of the air flow on: thegrain shell due.

to the cyclic variation of the flow speed, density and pressure.

The exit hole of the mixing tube should preferably be grain huller withreferences to the appended drawing which is a schematic representationof the huller according to the invention shown in a longitudinalsection.

Th air-blast grain huller comprises a chamber 1 terminating in a nozzle2, and a mixing tube 3 with a channel 4 disposed in a substantiallyvertical position. Tube 3 is provided with a contractor 5 located at theentry of the unscoured grain into channel 4 (the direction of grainentry and exit being shown at A in the figure).

Chamber 1 is fitted with a socket 6 to feed therethrough compressed airwhich then issues through hole 7 of nozzle 2, the latter being locatedwithin contractor 5.

To increase the amount of injected grain, placed in hole 7 coaxiallywith nozzle 2 is a stem 8. Stem 8 is disposed in nozzle 2 so as to becapable of adjustment displacements, one end 9 of stem 8 being locatedwithin contractor 5 and made narrowing along axis 0--0 in the directionaway from nozzle 2 toward channel 4 of tube 3, while the other end 10 isthreaded and fitted with a hand-wheel 11 by which it is screwed into ahole made in chamber 1.

Channel 4 expands stepwise downward along axis 0-0. In the places ofpassage from a step B of channel 4 to another step C (the number ofsteps in this device can be chosen arbitrarily, only two being shown inthe figure) there are provided ports 12 for additional air injectioninto the channel, the sectional area of channel 13 in step B being lessthan that of channel 14 in step C. Such a stepwise-expanding shape ofchannel 4 reduces its aerodynamic resistance and raises the utilizationfactor of the air jet energy.

Each step B and C of channel 4 is formed by separate mixing tubes 15 and16. These tubes 15 and 16 are mounted so, that the end of the precedingtube 15 is located in a contractor 17 of the subsequent tube 16, thehole 12 being formed by this contractor 17 and the lower edge of themixing tube.

Each tube 15 and 16 is made as a series of sleeves l8 enclosed in acasing 19 and retained therein by a nut 20.

The mixing tube 16 forming the step C is assembled of alternatingsleeves 21 and 22 having holes of two different diameters D, and Drespectively, the thus formed channel having a stepped shape. Sleeves 21and 22 are made of an abrasive material.

To reduce the speed of the hulled grain movement the exit hole of tube16 is provided with a diffuser 23.

The grain huller operates as follows.

As grain is fed into contractor 5 in the direction shown by arrow A, andcompressed air is supplied thorugh socket 6, air flows at a supersonicspeed through the annular slit formed by hole 7 of nozzle 2 and thenarrow end 9 of stem 8, the grain being thus injected from contractor 5into channel 13 of tube 15 which is formed by the holes of sleeves 18.While the grain moves along stem 8 and tube 15 it is partially hulled bythe effect of the impact of jets, the difference of pressures in the jetand under the grain shell, the in-, ertial loads on the grain, andfriction of its shell against the walls of sleeves 18.

Due to the provision of stem 8 in the grain feeding zone the grainsarriving at the air jet and having different directions and speeds donot impede each others entry into the jet, which permits raising grainconcen tration in the air jet, and reducing grain stirring in contractor5 and energy losses therein.

Issuing from channel 13 of tube 15 is a double-phase flow (air grain)which enters channel 14 of the other tube 16 mounted coaxially with thefirst one.

Owing to the abrupt change of the sectional area of channel 14 withrespect to channel 13, as well as to the additional air injection intothe flow through port 12, shock waves are produced which strip the grainshells, their strength and bond having been pre-weakened in channel 13of tube 15.

On arrival at channel 14 of tube 16 the air flow in the course of itsmovement through the holes of sleeves 21 and 22 is subject to cyclicallyalternating compression and expansion causing sharp cyclic oscillations,i.e., alternating drops and rises, of the air velocity, pressure, anddensity which repeatedly occur along channel 14.

Thus, the forces acting on the grain shells due to variation of saidparameters (velocity, pressure, density) acquire a cyclic pulsed nature,which essentially intensities the hulling process, the shells beingstripped even from such grains where they have grown tight with thekernel. The use of abrasive material for the'sleeves promotes frictionof the grains against the walls of channel 14 in tube 16, which furtherintensities the hulling process.

As the double-phase flow moves along diffuser 23 it loses speed, thusprecluding the splitting of the hulled grain.

What we claim is:

1. An air-blast grain huller, comprising: a chamber with means forsupplying compressed air into said chamber; a nozzle communicating withsaid chamber and having an orifice for discharging air from said chamberand creating a stream of air for hulling grain; a mixing tube forhulling grain by said stream of air discharged from said nozzle, saidtube being arranged substantially vertically under said chamber andhaving a channel with several sections of circular cross-sectionsarranged one above another, the diameter of a section below a highersection being greater than the diameter of said higher section; ports insaid tube and located in the places of transition from one section ofthe channel to another for passing additional injected air into saidchannel; a funnel-shaped member in said mixing tube for feeding graininto said channel, said funnel-shaped member containing said nozzle; astem arranged in the orifice of said nozzle and coaxial with the axis ofsaid nozzle, one end of said stem being held in said chamber, and theother end of said stem projecting in said funnel-shaped member; eachsection of said channel being formed by a separate auxiliary tube withoutlet hole mounted so that the outlet hole of the preceding tube islocated within the following one, said ports for passing additionalinjected air into said channel being formed partially by the lower partsof the auxiliary tubes; each auxiliary tube comprising a series ofsleeves enclosed in a casing; said sleeves being made of abrasivematerial; said sleeves of each auxiliary tube, starting from the secondone, having holes of two different diameters and being installedalternately so that the diameter of the channel section jointly formedby them alternately grows and decreases stepwise in a downwarddirection.

1. An air-blast grain huller, comprising: a chamber with means for supplying compressed air into said chamber; a nozzle communicating with said chamber and having an orifice for discharging air from said chamber and creating a stream of air for hulling grain; a mixing tube for hulling grain by said stream of air discharged from said nozzle, said tube being arranged substantially vertically under said chamber and having a channel with several sections of circular cross-sections arranged one above another, the diameter of a section below a higher section being greater than the diameter of said higher section; ports in said tube and located in the places of transition from one section of the channel to another for passing additional injected air into said channel; a funnel-shaped member in said mixing tube for feeding grain into said channel, said funnel-shaped member containing said nozzle; a stem arranged in the orifice of said nozzle and coaxial with the axis of said nozzle, one end of said stem being held in said chamber, and the other end of said stem projecting in said funnel-shaped member; each section of said channel being formed by a separate auxiliary tube with outlet hole mounted so that the outlet hole of the preceding tube is located within the following one, said ports for passing additional injected air into said channel being formed partially by the lower parts of the auxiliary tubes; each auxiliary tube comprising a series of sleeves enclosed in a casing; said sleeves being made of abrasive material; said sleeves of each auxiliary tube, starting from the second one, having holes of two different diameters and being installed alternately so that the diameter of the channel section jointly formed by them alternately grows and decreases stepwise in a downward direction. 